Magnetic head coil and structure for protecting same during pole notch processing

ABSTRACT

A system and method are provided for manufacturing a magnetic head. Initially, a coil structure, a first pole layer, and a gap layer are formed. A second pole layer is then deposited to form a pair of flanking portions flanking a central portion of the second pole layer. Thereafter, the second pole layer is masked with a photoresist layer. During manufacture, the flanking portions of the second pole layer work in conjunction with the photoresist layer to substantially protect the coil structure from damage.

FIELD OF THE INVENTION

The present invention relates to magnetic head coil structures, and moreparticularly, this invention relates to protecting magnetic head coilstructures during related processing.

BACKGROUND OF THE INVENTION

In a magnetic recording disk drive, data is written by thin filmmagnetic transducers called “heads”, which are supported over a surfaceof the disk while it is rotated at a high speed. The heads are supportedby a thin cushion of air (an “air bearing”) produced by the disk's highrotational speed.

FIG. 1 illustrates a prior art MR head, which may be employed as amagnetic head on a slider. The head 30B has a pole tip region, aninsulation stack region and a coil region, the pole tip region extendingfrom the ABS to the insulation stack region, the insulation stack regionextending from the pole tip region to the back gap (not shown) and thecoil region located in the insulation stack region but spaced from thepole tip region. In the present framework, the first and second shieldlayers S1 and S2 are located in the pole tip region for the protectionof the MR sensor. The first shield S1 terminates between the pole tipregion and the coil region along a slope 50. This provides a sunken ordepressed area 51 for subsequent thin film layers of the head whichmakeup the insulation stack. The second gap layer G2 extends along theslope 50 of the first shield S1, thence perpendicular to the ABS towarda back region of the head. It should be noted that leads are not shownfollowing the same path. The leads for the head 30B may take a differentpath.

The layer S2/P1, write gap, insulation layer I1, write coil, insulationlayers I2 and I3, and the second pole piece P2 are all recessed by thedepression provided by the first shield layer S1 in the insulation stackregion lowering the height of the second pole piece above the write gapplane so as to enhance planarization of the second pole tip PT2. Thissignificantly reduces the aspect ratio of the resist during fabricationof the pole tip PT2, enabling construction of the pole tip at the ABSwith a thin layer of resist, in the order of 4 um as seen by thethickness of the resist layer 40 at the ABS. A thinner resist layerpermits a narrower pole tip to be precisely constructed with gooddefinition, thereby enhancing the bit density of the head. Of furthersignificance, is elimination of a large portion of the first shieldlayer S1, which reduces the induction that opposes the operation of thewrite coil. The portion of the first shield layer S1 remaining is remotefrom the write coil so that when high frequency currents are conductedthrough the write coil, its EMF is not significantly opposed by the CEMFof the first shield S1.

The slope 50 of the first shield S1 may be constructed by a resist layerwith a negative slope. Permalloy may then be plated adjacent thenegative slope, after which the resist is removed to produce the slope50 of the first shield S1.

Prior art FIG. 2A illustrates a top view of the MR head of FIG. 1. Asshown, an end 201 of the top pole layer P2 extends farther toward thecoil 202 with respect to the flanking portions of the bottom pole layerP1. In use, a photoresist layer that is deposited over the coil 202 forcreating the notched pole tip PT1 b adhesively couples to the end 201 ofthe top pole layer P2. However, it fails to reach ends 203 of the bottompole layer P1. This results in the exposure of the coil 202 during ionbeam milling that is used to create the notched pole tip PT1 b.

Prior art FIG. 2B is a cross-sectional view taken along line 2B—2B ofFIG. 2A which illustrates the manner in which the ion beams 200 erodethe coil 202 during the processing of the structure of FIG. 1. As shown,a primary contributor of this problem is the fact that it is extremelydifficult to mask a photoresist layer tightly against an edge of thebottom pole layer P1.

Prior art FIG. 2C illustrates actual damage 204 to the coil structure202 resulting from the above problem. It should be further noted thatsince the coil structure 202 is closer and tighter to the bottom pole,any damage to the coil structure 202 has significant ramifications ondata rates and overwriting operations.

There is thus a need for a magnetic head structure and a method ofmanufacturing the same that avoids damage to a coil structure during ionbeam formation of a notched pole tip.

DISCLOSURE OF THE INVENTION

A system and method are provided for manufacturing a magnetic head.Initially, a coil structure, a first pole layer, and a gap layer areformed. A second pole layer is then deposited to form a pair of flankingportions flanking a central portion of the second pole layer.Thereafter, the second pole layer is masked with a photoresist layer.During manufacture, the flanking portions of the second pole layer workin conjunction with the photoresist layer to substantially protect thecoil structure from damage.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of the presentinvention, as well as the preferred mode of use, reference should bemade to the following detailed description read in conjunction with theaccompanying drawings. It should be noted that at least a portion of thefollowing drawings are not drawn to scale.

FIG. 1 illustrates a prior art “merged” magnetoresistive (MR)read/inductive write head.

Prior art FIG. 2A illustrates a top view of the MR head of FIG. 1.

Prior art FIG. 2B is a cross-sectional view taken along line 2B—2B ofFIG. 2A which illustrates the manner in which the ion beams erode thecoil during the processing of the structure of FIG. 1.

Prior art FIG. 2C illustrates actual damage to a coil structure.

FIG. 3 shows a disk drive, in accordance with one embodiment.

FIG. 4 illustrates a method for preventing damage to a head coilstructure during ion milling a first pole notch, in accordance with oneembodiment.

FIG. 5 illustrates the dams that are formed in addition to the secondpole layer in operation 460 of FIG. 4, in accordance with oneembodiment.

FIG. 6 is a cross-sectional view taken along line 6—6 shown in FIG. 5,which shows the manner in which the dams formed by the second pole layerabut the photoresist layer for protecting the coil structure from theion milling during the notching of the first pole layer.

FIG. 7 illustrates the resultant coil structure which shows no damage asa result of the foregoing process.

BEST MODE FOR CARRYING OUT THE INVENTION

The following description is the best embodiment presently contemplatedfor carrying out the present invention. This description is made for thepurpose of illustrating the general principles of the present inventionand is not meant to limit the inventive concepts claimed herein.

Referring now to FIG. 3, there is shown a disk drive 300 embodying thepresent invention. As shown in FIG. 3, at least one rotatable magneticdisk 312 is supported on a spindle 314 and rotated by a disk drive motor318. The magnetic recording media on each disk is in the form of anannular pattern of concentric data tracks (not shown) on disk 312.

At least one slider 313 is positioned on the disk 312, each slider 313supporting one or more magnetic read/write heads 321. More informationregarding such heads 321 will be set forth hereinafter during referenceto FIG. 4. As the disks rotate, slider 313 is moved radially in and outover disk surface 322 so that heads 321 may access different portions ofthe disk where desired data are recorded.

Each slider 313 is attached to an actuator arm 319 by way of asuspension 315. The suspension 315 provides a slight spring force whichbiases slider 313 against the disk surface 322. Each actuator arm 319 isattached to an actuator 327. The actuator 327 as shown in FIG. 3 may bea voice coil motor (VCM). The VCM comprises a coil movable within afixed magnetic field, the direction and speed of the coil movementsbeing controlled by the motor current signals supplied by controller329.

During operation of the disk storage system, the rotation of disk 312generates an air bearing between slider 313 and disk surface 322 whichexerts an upward force or lift on the slider. The air bearing thuscounter-balances the slight spring force of suspension 315 and supportsslider 313 off and slightly above the disk surface by a small,substantially constant spacing during normal operation.

The various components of the disk storage system are controlled inoperation by control signals generated by control unit 329, such asaccess control signals and internal clock signals. Typically, controlunit 329 comprises logic control circuits, storage and a microprocessor.

The control unit 329 generates control signals to control various systemoperations such as drive motor control signals on line 323 and headposition and seek control signals on line 328. The control signals online 328 provide the desired current profiles to optimally move andposition slider 313 to the desired data track on disk 312. Read andwrite signals are communicated to and from read/write heads 321 by wayof recording channel 325.

The above description of a magnetic disk storage system, and theaccompanying illustration of FIG. 3 are for representation purposesonly. It should be apparent that disk storage systems may contain alarge number of disks and actuators, and each actuator may support anumber of sliders.

FIG. 4 illustrates a method 450 for preventing damage to a head coilstructure during ion milling a first pole notch, in accordance with oneembodiment. While such method 450 may be carried out in the context ofheads 321 of FIG. 3, it should be noted that the method 450 may furtherbe employed in any desired context.

Initially, a coil structure is formed on lower layers in any desiredmanner such as that shown in FIG. 1. See operation 451. As shown, afirst pole layer and a gap layer are deposited in operations 452 and454. The gap layer may be constructed utilizing any desired materialsuch as alumina or the like. Further, it should be noted that theforegoing operations may be carried out in any desired manner.

Next, the second pole layer is deposited in operation 460 using masks,etc. The second pole layer is preferably deposited such that a pair ofdams is formed for reasons that will soon become apparent. It should benoted that the second pole layer and the dams may be constructedutilizing a Permalloy or any desired material known to those of ordinaryskill in the art.

FIG. 5 illustrates the dams 500 that are formed in addition to thesecond pole layer P2 in operation 460 of FIG. 4, in accordance with oneembodiment. As shown in FIG. 5, the dams 500 flank a flare point 502 ofthe second pole layer P2. The dams 500 are slightly spaced from theflare point 502 and extend outwardly therefrom with a slightly arcuateconfiguration. Ideally, such arcuate design follows and is contiguouswith an arc associated with a periphery of the coil structure 504.

As an option, the dams 500 defined by the second pole layer P2 mayextend at least 10 um toward the coil structure with respect to an endof a pole tip defined by the notch which resides adjacent the coilstructure 504. Moreover, to ensure that the dams 500 do not cause anymagnetic performance degradation, the dams 500 may be spaced a lateraldistance of at least 0.5 um from the flare point 502 of the second polelayer P2.

With continuing reference to FIG. 4, the second pole layer is thenmasked with a photoresist layer. Note operation 462. As best shown inFIG. 5, the location to be masked in operation 462 is that including thesecond pole layer P2 and excluding the first pole layer P1.

Next, operation 464, notching is carried out in the area of the firstpole layer P1 that is exposed by the mask. The notching may be carriedout utilizing ion milling or any desired process.

The criticality of the dams is thus realized during the deposition ofthe photoresist mask during operation 462, and the notching of operation464. In particular, the second pole layer that forms the “dams” residessufficiently close to the coil structure 504 in order to adhesivelycouple to the photoresist layer. In the context of the presentinvention, it is imperative to note that photoresist exhibits an“adhesive” property, whereby the photoresist abuts and “sticks” to thedams. This is vital so that the photoresist layer is capable ofprotecting the coil structure 504 from the ion milling. See operation466.

FIG. 6 is a cross-sectional view taken along line 6—6 shown in FIG. 5,which shows the manner in which the dams 602 formed by the second polelayer P2 abut the photoresist layer 600 for protecting the coilstructure 504 from the ion milling 604 during the notching of the firstpole layer P1.

FIG. 7 illustrates the resultant coil structure 504 which shows nodamage as a result of the foregoing process.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of a preferred embodiment shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims and theirequivalents.

1. An apparatus, comprising: a coil structure; a first pole layersituated on the coil structure; a gap layer situated on the first polelayer and the coil structure; and a second pole layer configured to forma pair of dams flanking a central portion of the second pole layer andadapted to substantially protect the coil structure from damage duringmanufacture.
 2. The apparatus as recited in claim 1, wherein the coilstructure includes a sunken coil structure.
 3. The apparatus as recitedin claim 1, wherein the dams of the second pole layer are arcuate dams.4. The apparatus as recited in claim 1, wherein the dams of the secondpole layer are spaced from the central portion of the second pole layerat least 0.5 um to prevent magnetic performance degradation.
 5. Theapparatus as recited in claim 1, wherein the dams of the second polelayer are adhesively coupled to a photoresist layer to ensure that thephotoresist layer substantially protects the coil structure from damageduring manufacture.
 6. The apparatus as recited in claim 1, wherein anotch is formed in the first pole layer.
 7. The apparatus as recited inclaim 6, wherein the notch is formed in the first pole layer utilizingion milling, a photoresist layer substantially protecting the coilstructure from damage caused by the ion milling.
 8. The apparatus asrecited in claim 7, wherein the dams of the second pole layer extend atleast 10 um toward the coil structure with respect to an end of a poletip defined by the notch which resides adjacent the coil structure.
 9. Adisk drive system, comprising: a magnetic recording disk; a magnetichead including: a coil structure, a first pole layer situated on thecoil structure, a gap layer situated on the first pole layer and thecoil structure, and a second pole layer configured to form a pair ofdams flanking a central portion of the second pole layer and adapted tosubstantially protect the coil structure from damage during manufacture;an actuator for moving the magnetic head across the magnetic recordingdisk so the magnetic head may access different regions of the magneticrecording disk; and a controller electrically coupled to the magnetichead.